Voltage controlled oscillators (VCOs) are widely used in radio transceivers. When implemented to support radio transmission, for example, a VCO must typically be calibrated or “tuned” to an appropriate transmit frequency prior to commencement of a transmit cycle. As a result, in a mobile device radio utilizing a secure frequency hopping transmission protocol, such as spread-spectrum cellular communications, or shorter range Bluetooth communications, for example, VCO calibration may need to occur up to a thousand times per second, with each calibration sequence drawing some energy from the mobile device battery.
Although power conservation is important for substantially all battery powered mobile communication devices, it may be a particularly critical issue for personal area network (PAN) communication devices employing Bluetooth and the newer Bluetooth Low Energy (BLE) technologies, for example. Such devices typically rely on very small batteries to support short-range communications, and must keep their power overheads to a minimum. In order to meet the stringent power budgets of these newer communication devices while also enabling the advantageous data security provided by frequency hopping transmission protocols, solutions with a faster VCO calibration is needed.